CAUSE CELEB: Justine Leguizamo, wife of actor John Leguizamo, is part of a new conservancy that will help fund Washington Square Park. Photo: Reuters

(Christian Johnston)

The city’s famed bohemian playground is about to conform.

The Parks Department has secretly formed a private conservancy to help fund Washington Square Park with the help of actor John Leguizamo’s wife, Justine, and socialite Veronica Bulgari.

Advocates have long resisted a park nonprofit and say it will “sterilize” the Village’s beatnik stomping ground.

“If any park was going to avoid the [conservancy] formula, it was Washington Square Park,” said Cathryn Swan, who writes on Washington Square Park Blog, a site dedicated to the square. “Does every park in New York City have to be cookie cutter?”

But Justine Leguizamo told The Post that she considers her group not a private club but an opportunity to bring neighbors together.

“We want the park to be clean, safe and beautiful,” said Leguizamo, also on the board of the Greenwich Village Society for Historic Preservation. “We want to work with the community to make this park as great as it can be.”

Last week, Manhattan Borough Park Commissioner Bill Castro admitted that a conservancy was in the works.

Neighbors stumbled upon its existence last month, when park administrator Sarah Neilson added “executive director of Washington Park Conservancy” to her voice mail and signature.

Neilson, who makes $88,000 a year, was recently hired by the city to serve as park administrator and conservancy director.

Park officials met privately with the nonprofit’s founders because they feared a public backlash could halt talks, one insider said.

Conservancy founder Elizabeth Ely said she’s seeking donations and volunteers to plant a garden and bring events to the green.

“The city runs the park. This is just to give it a boost to help,” said Ely, a retired interior designer. “We’re happy for everybody to work with us. We hope it’s a big community lovefest.”

But Geoffrey Croft of NYC Park Advocates is concerned.

“It’s the city’s job to take care of its parks. When you give up control of day-to-day operations, there’s even less transparency,” he said.

The nonprofit will help maintain lawns, plants and playgrounds and fund a staffer to organize children’s activities and yoga, Pilates and tai chi classes in the summer.

More than 70 private foundations contributed $165 million to the city’s parks and public spaces in 2011, a Parks spokesman said.

Conservancies collect private donations, taxpayer-funded grants and fees from food kiosks and venues — and they’re cash cows for the people who run them.

Bryant Park Corp. President Daniel Biederman pulled in $240,701 in pay and benefits in the fiscal year ending June 30, 2011 — on top of his $230,701 package as head of the 34th Street Partnership.

Aimee Boden got $62,745 as executive director of the Randall’s Island Sports Foundation in 2011, while making $122,807 as a city park administrator, tax forms say.

As the Parks Department seeks private donations for Washington Square Park, the agency is also cracking down on the bohemian buskers who call it home.

Beginning May 8, street performers must stay at least 50 feet from art installations, monuments and fountains in city parks and at least five feet from park furniture or face fines.

“In terms of privatization and sterilization, it’s pretty clear what they have in mind,” said Robert Lederman, an artist who’s battled the city over the rules in court for years. “The Parks Department is really just a private agency at this point.”